Autism spectrum disorder impacts the nervous system and affects the overall cognitive, emotional, social and physical health of the affected individual.The range and severity of symptoms can vary widely. Common symptoms include difficulty with communication, difficulty with social interactions, obsessive interests and repetitive behaviours.Early recognition, as well as behavioural, educational and family therapies may reduce symptoms and support development and learning. Prior to that, they were categorized as five different types of autism: autistic disorder, pervasive developmental disorder-not otherwise specified (PDD-NOS), Asperger syndrome, Childhood Disintegrative Disorder and Rett Syndrome (a rare genetic disorder). Studies on autism have tended to focus either on those with intellectual disability (ie, those with intellectual quotient [IQ] under 70) or on the group that is referred to as “high-functioning”, that is, those with borderline, average or above average IQ